TLR4 signaling promotes secretion of VEGF/IL-8 in prostate cancer PC3 cells and related mechanism / 第二军医大学学报

ABSTRACT

Objective: To study TLR4 expression in human prostate cancer PC3 cells and the related intracellular signaling mechanisms. Methods: Human prostate cancer PC3 cells were stimulated with TLR4-specific ligand lipopolysaccharide (LPS), then the cells and supernatants were collected 0, 2, 6, 12, 24, and 48 hours after LPS stimulation. TLR4 mRNA and protein expression was examined by reverse transcription-PCR and Western blotting analysis, respectively. The mRNA expression of TGF-β, VEGF, 1L-8, COX-2, and MMP3 was also measured by reverse transcription-PCR, and the levels of VEGF, IL-8 in the supernatants were examined by ELISA. To further study the related signaling pathway, MAPK and NF-κB signaling pathways were blocked by specific inhibitors in PC3 cells before LPS stimulations the cells were collected after 4 hours and the supernatants were collected after 24 hours; and the above mentioned factors were examined by reverse transcription-PCR and ELISA again. Results: TLR4 expression was up-regulated by LPS stimulation in human prostate cancer PC3 cells, which significantly increased mRNA expression of TGF-β, VEGF, IL-8, COX-2, and MMP3 and secretion of VEGF and IL-8 in the supernatants (P<0.05); further study showed that p38 MAPK and NF-κB signal pathways were involved in the process. Conclusion: TLR4 signaling promotes VEGF and IL-8 secretion through p38 MAPK and NF-κB signal pathways.